Nitrogen fixation by Paenibacillus polymyxa WLY78 is responsible for cucumber growth promotion

To study nitrogen contribution to cucumber derived from fixation of Paenibacillus polymyxa WLY78. The nif gene cluster deletion mutant (?nifB-V) WLY78 was constructed by a homologous recombination method. effects plant-growth promotion were investigated greenhouse experiments. estimated 15N isotope dilution method (also being called the natural abundance technique). Deletion P. resulted in complete loss nitrogenase activity. Greenhouse experiments showed that inoculation with could significantly enhance lengths and dry weights roots shoots, but ?nifB-V not. plants derive 25.93% performed WLY78, nearly not provide for plant growth. This present demonstrated contributes